This invention relates in general to sewing devices and in particular to a new and useful sewing assembly which includes a sewing machine which is movable along the work.
A sewing assembly similar to the present invention is disclosed in U.S. Pat. No. 4,416,125. That prior art sewing assembly forms a part of an automatic machine for letting out furskins. The sewing machine for sewing together furskin strips is displaceably supported on a horizontal guide rail and a splined shaft parallel thereto. The splined shaft is connected to a motor and drives through an internally geared wheel the mechanism of the sewing machine. The sewing machine is connected through a cog belt to a stepping motor by which the sewing machine is displaced intermittently in synchronism with the stitch formation along the furskin strips clamped in a holding device.
Experience has shown that with such drive systems, because of the elasticity of the cog belt, the transmission of the intermittent advance movements of the stepping motor becomes increasingly inaccurate with the increasing amount of displacement, thus the increasing length of the cog belt. In addition, such a drive system tends to oscillate at certain frequencies. Further, the use of a stepping motor requires an expensive control circuit for synchronizing the individual advance steps with the stitch forming operation of the machine.